IntelliJ IDEA 2016.3 Help

Palette

The Component Palette is a tool window which appears by default at the right side of the frame next to
the
Form Workspace. It contains UI components which
you can visually place on a Form.
The default Group of the Palette contains a set of Swing user interface components that
you can arrange on forms as needed. The Swing group also has horizontal and vertical Spacers that you
can
place on the form to define space between components. (These can
behave differently depending on the setting in the Layout Manager property of the container into which a
spacer is placed.) You can customize the Component Palette to contain
additional groups, and your own and/or third-party GUI components (see
Customizing the Palette).

The context menu of the Palette tool window provides functions for
managing components and groupings. Two groups are
present by default:

Swing: contains components from the Swing component library.

Palette: contains a single component labeled Non-Palette component. When you
select this component and add it to a Form,
a dialog appears in which you can select any component class accessible to your project, or any other
existing Form. This is useful in cases where you want to use
a component without adding it to the Component Palette.

If you have your own custom components, or if you reuse components from third-party libraries, you can add
them to the Component Palette via the context menu,
which also enables you to add component groups. For more information, see Customizing the Component Palette.